Liability,culpability, and luck

Philosophical Studies - This paper focuses on the role of culpability in determining the degree of liability to defensive harm, and asks whether there are any restrictions on when culpability is...     

Does interference between self and other perspectives in theory of mind tasks reflect a common underlying process? Evidence from individual differences in theory of mind and inhibitory control

Theory of mind (ToM), the ability to understand that other agents have different beliefs, desires, and knowledge than oneself, has been extensively researched. Theory of mind tasks involve participants dealing with interference between their self-perspective and another agent’s perspective, and this interference has been related to executive function, particularly to inhibitory control. This study assessed whether there are individual differences in self–other interference, and whether these effects are due to individual differences in executive function. A total of 142 participants completed two ToM (the director task and a Level 1 visual perspective-taking task), which both involve self–other interference, and a battery of inhibitory control tasks. The relationships between the tasks were examined using path analysis. Results showed that the self–other interference effects of the two ToM tasks were dissociable, with individual differences in performance on the ToM tasks being unrelated and performance in each predicted by different inhibitory control tasks. We suggest that self–other differences are part of the nature of ToM tasks, but self–other interference is not a unitary construct. Instead, self–other differences result in interference effects in various ways and at different stages of processing, and these effects may not be a major limiting step for adults’ performance on typical ToM tasks. Further work is needed to assess other factors that may limit adults’ ToM performance and hence explain individual differences in social ability.

     

Speech comprehension difficulties in older adults: cognitive slowing or age-related changes in hearing?

Speech comprehension declines more rapidly in older adults than in younger adults as speech rate increases. This effect is usually attributed to a slowing of brain function with age. Alternatively, this Age X Speed interaction could reflect the inability of the older adult's auditory system to cope with speed-induced stimulus degradation. When the authors speeded speech in a way that produced minimal degradation, both age groups were equally affected. However, when speech was speeded using other methods, word identification declined more in older than in younger adults. Hence, auditory decline rather than cognitive slowing may be responsible for older adults' poorer performance in speeded conditions.     

Eye movements in natural behavior

The classic experiments of Yarbus over 50 years ago revealed that saccadic eye movements reflect cognitive processes. But it is only recently that three separate advances have greatly expanded our understanding of the intricate role of eye movements in cognitive function. The first is the demonstration of the pervasive role of the task in guiding where and when to fixate. The second has been the recognition of the role of internal reward in guiding eye and body movements, revealed especially in neurophysiological studies. The third important advance has been the theoretical developments in the fields of reinforcement learning and graphic simulation. All of these advances are proving crucial for understanding how behavioral programs control the selection of visual information.     

Effect of upcoming reward type when rats press a lever for ethanol

Rats' operant responding for sucrose rewards in the 1st half of a session can vary directly with the conditions of reward in the 2nd half. The authors investigated whether that induction effect represented an animal model of emotive states. Rats pressed a lever for either ethanol or sucrose rewards in the 1st half of a 40-min session. The reward in the 2nd half of the session was, across conditions, 1% sucrose, a food pellet, or the same reinforcer delivered in the 1st half. When subjects responded for sucrose, upcoming reward type had little influence on responding in the 1st half of the session. However, when subjects responded for ethanol, upcoming 1% sucrose and food-pellet reinforcement both produced increases in responding. The results suggest that the procedure produced different emotive states, but further work is needed to support such a model. The results also have potential applied implications.     

Perirhinal cortex lesions impair context aversion learning

Rats with perirhinal cortex lesions were compared with sham controls on a conditional discrimination in which saccharin was paired with LiCl in context 1, but paired with saline in context 2. Perirhinal-lesioned rats were slightly slower to acquire the discrimination but reached control levels by the end of acquisition. Both groups showed transfer to familiar tap water, consuming less in context 1 than in context 2. Unlike sham rats, perirhinal rats failed to show an aversion to context 1 on a place choice test. These data provide neuroanatomical support for the postulated difference between Pavlovian conditioning and conditional learning.